Complex silver salts of alpha-amino acids



I "Mamet. i n nmw n' 'mnnxus eueennnnnt or nasnn, SWITZERLAND. ASSIGNOB. fro-ran norrnaivn-na nocnn i can wonns, or new roan, N. 2., a coaroaarron or new roan.

" ".comnnx SILVER snn'rs or (ii-Amino Acres. T

To all w /tom it concern Y HEIM, acitizen of Switzerland, and a resident of Basel, Switzerland, have invented certain new and useful Improvements in Complex Silver Salts ofa-Amino Acids, of

which the following is a specification.- Complex silver salts of a-amino, acidshave heretofore been mnknown. It has already been described (Curtius,,Journal fur praktische. Chemie, Neue Folge, vol. 26, 1882, pages 164-167) that glycin is brought to act upon silver oxidepwhereby the reaction product is boiled dovvntill crystallization of the silver amino acetate sets in. The

silver salt resulting therefrom and containing 59.33% of silver is, however, the normal silver salt of amino acetic acid and does not contain the silver in complex binding.

It has been found that by. causing an exc'ess-of oa-amino acids to act upon silver oxide as Well as upon different organic and inorplex silver salts from an excessof a-amino gani-c silver salts, complex. silver salts of oz-amino acids may be obtained;

The conditions. for the formation of comacids vary according to the silver compound chosen as starting material.

The formation of the complex salt generally'makes itself noticed by an easier solubility of the reaction product. It may further be ascertained by the fact that the aqueous silver'salts no longer answerto all reactions of the silver cation. So for instance the addition of a solution of sodium in that they are a great deal more stable than the aqueous solutions of silver salts; @n being left to stand for some time no reduced silver is precipitated. The complex silvercompounds of a-amino acids do not precipitate albumin. They have no irritatsome considerable length .of time. separating the silver compound the mother Specification of Letters Patent. I Pat nt d my 23, T9922.

Application filed September 3011919. Serial No. 327,557.

a ing efiectiupon the membranes. Be i known that I, MARKUs Guocau- This latterpropertyas Well as their stabilityrender them suitable for therapeutic purposes. Y

75 parts of glycin' are dissolved in 120 parts of Water and to this solution are added 23 parts of silver oxide freshly precipitated. 0n heating the silver oxide isnearlyall dissolved. The hot solution is filtered, put into a freezing mixture and caused quickly to coagulate by stirring. A. colorless salt in the shape of small white plates is precipitated. After being separated from the mother 'liqnor the crystals arewashed with a little Water and, in the given case, crystallized from Watercontaining glycin. In order to obtain a good yield of the complex silver compound it is advisable not to use more than 3 equivalent of silver oxide to one equivalent of glycin. One may also start from Curtiuss silver salt and cool this quickly belovv 0 C. in presence of an excess of glycin, in order to obtain the more stable silver compound. I

The complex silver compound dissolves .pretty easily in Water. Thesolubility is rendered still greater by the addition of glycin or an other oz amino acid. The aqueous solution has an alkaline reaction upon litmus. On the addition of a solution of sodium hydroxide or sodium carbonate the solution does not become turbid until after After liquor may again be saturated with glycin and by the addition of silver oxide further quantities of the complex silver compound may be obtained.

Example 2.

17 parts of silver nitrate are dissolved in a little Water, added to a saturated solution of 37.2 parts of glycin'and boiled down in vacuo at a moderate temperature. The crystalline mass thereby obtained is easily soluble in Water its reaction is neutral. The addition of a solution of sodium hydroxide or sodium carbonate produces no precipitate.

silver salicylate together with 75 parts of sium chloride, .01 g. of calcium chloric e and.

.G g. of sodium chloride in 1Q0 ccm. of water), produces a milky preclpitate of s11- ver chloride.

E sample 3.

15.6 parts of silver sulfate are. finely ground with parts of glycin. The mixture is much more easily soluble in water than the silver sulfate and shows the same reactions as the complex silver compound described in Example 1.

E wample 4.

By pulverizing a-alanin with an equivalent quantity of freshly precipitated s1lver oxide the silver salt of alanin CH CH- (NHQCOO Ag is produced. 36 parts of a-alanin are dissolved in'as little water as possible and 19.2 parts of the silver alanin added to the concentrated solution. The salt ,is easily dissolved. The reaction product is thenfiltered and boiled. down till dry; it will then show a slight brown coloring. The remaining crystall1ne mass is easily soluble in water and'reacts 1n the same manner as the corresponding silver compound of glycin.

Example 5.

27.4 parts of silver carbamide are carefully ground together with 75 parts of glycin. A light yellow powder is obtalned, which is soluble in waterin the proportion of 3:100. Silver carbamide itself does not dissolve in water. The aqueous solution is colorless. Its reaction upon litmus is alkaline. With a solution of sodium hydroxide it remains clear.

Example 6'.

16.8 parts of silver acetate are dissolved with 37.5 parts of glycin in water and boiled down in vacuo at a temperature not exceeding 30 0., light being excluded. There remains a white powder, the solubility of which in water is about five time greater than that of silver acetate. The reaction of the solution upon litmus is slightly alkaline, with a solution of sodium hydroxide it remains clear.

} Example 7'.- In order to produce the complex glycin silver salicylate one grinds 24:.6 parts of glycin. A white powder is obtained, which is more easily soluble in water than silver salicylate. The solution remains clear with sodium hydroxide solution and its reaction upon litmus, is neutral.

In the same manner the other oc-amino acids may be usedfor the manufacture of complex silver'salts. With aromatid' amino acids (anthranilic acid, para-amino benzoic acid) it is not possible to Qbtain s mpIex compounds, likewise not with betaines.

When in my claims I refer to non-comv plex silver compoundsi, I refer to the silver compounds which, ashereinabove disclosed, are used 1n my process, namely silver oxide,

organic silver salts and inorganic silver salts.

When I refer, in m claims, to the use of a sufiicient excess 0 oa-amino acid, I mean that the excess mustbe such as to make. possible the formation of the complex silver salts hereinabove described. I claim 1 .As new products the complex silver salts V of oz-amino acids Which can be obtained by, treating non-complex. silver compounds with a quantity of oz-amino acid whose weight is not less than at least five times the weight of such compounds. (calculated as silver oxide actually or potentiallyp-resent therein) which would be needed to form the corresponding normal salts, which complex salts have the following characteristics: they are much more easily soluble than the normal silver salts of oz-amino acids; their solutions are more stable than those of the normal silver salts of oa-amino acids;

they do not precipitate albumin, and have no irritating effect upon the mucous membrane.

2. As a new product the complex silver salt of glycin, which can be obtained by treating a non-complex silver compound with a quantity of glycin, whose weight is not less than at least five times the weight of such compound (calculated as silver oxide actually or potentially present therein) which would be needed to form the corresponding normal salt, which complex salt has the following characteristics: It is much more easily soluble than the normal silver salts of a-amino acids;- its solution ismore stable than that of the normal silver salts of a-amino acids; albumin, and has the mucous membrane.

3. The process for the manufacture of com-' plex sliver salts of a-amino acids which consists in treating a non-complex silver compound with a quantity of 'cz-amino acid whose weight is not less than at least five times the weight of such compound (calculated as silver oxide actually or potentially present therein) which would be needed to form the corresponding normal salt.

110 Y it does not precipitate. no irritating effect upon 4. The process for the manufacture of complex silver salts of a-amino acid which compotentially present therein) which would tees/see ing silver oxide with a quantity of glycin whose Weight is "not less than et least five times the weight of the silver oxide which would be needed to form the corresponding normal salt, and crystallizing the solution, obtained at a temperature below 0 C.

In witness whereof I have hereunto set my hand.

MARKUS GUGGENHEIM.

Witnesses HEINRICH KUBLI, ALBERT HOFFMANN. 

